The present invention is generally related to the field of heat sink clips and to their use in providing heat sink assemblies.
In prior heat sink assemblies, spring clips have been used to provide a clamping force to bias a surface of a power dissipation device, such as a semiconductor, against a heat sink surface. U.S. Pat. Nos. 3,519,889 and 3,572,428 illustrate prior heat sink clips which accomplish this general function. In addition, U or C shaped clips made of resilient spring material have been used to provide heat sink assemblies in which the arms of the clip essentially form a sandwich structure with the heat sink and power dissipation device being clamped therebetween. The use of such U or C shaped clips typically requires a minimum of additional mounting hardware and/or assembly labor as opposed to the use of mounting screws to attach heat dissipation plates of the power dissipation device to the heat sink.
In prior assemblies which utilize the spring action of U or C shaped clips to provide a heat sink assembly, typically the clip is opened by force applied to the ends or exterior projections of the clip arms, and then the clip is inserted over the power dissipation device and heat sink. In one prior assembly, a clip having one exterior projection is positioned such that a heat sink is between its arms. Then force is applied to the exterior projection to force the clip further open to permit insertion of a power transistor between the heat sink and the clip arm having the exterior projection. Then the applied force is released. In situations where there is insufficient room to grip the clip via a force provided exterior to the clip arms, the clip may still be used in a forced assembly type structure in which the clip is forceably slid over the combination of the heat sink and power dissipation device. However, such forced assemblies incur a high risk of damage to the power dissipation device. The prior art has not provided a viable alternative to the use of a simplified heat sink clip assembly relying on the compressive action between opposing arms of the clip when the assembly geometry prevents external access to the clip arms so as to open the clip and when providing a forced heat sink clip assembly is not desired.